In semiconductor package testing, a test contactor for testing various characteristics of the semiconductor package commonly uses spring loaded probe pins to provide an electrical interface between the tester channels of the test contactor and external leads of the semiconductor package. A semiconductor package to be tested is placed on an insulated package holder, and vacuum suction force is used to hold the package in place. The semiconductor package is then transferred to a test station where it is contacted by spring-loaded probe pins and tests relating to various characteristics of the semiconductor package are performed.
Conventionally, mechanical systems are used to provide external forces to physically hold the semiconductor package before contact by the probe pins, since the vacuum suction force is generally inadequate to overcome the contact force introduced by the spring-loaded probe pins to provide a stable contact for electrical tests.
In some situations, it may not be preferred for the semiconductor package that is being tested to be mechanically held, so as to avoid light emitted from the semiconductor package from being blocked by the mechanical system. When conducting optical tests, it may be necessary for all five sides of a semiconductor package, including its top surface and its four sides to emit light. In such circumstances, one prior art approach is to reduce the spring forces exerted by the probe pins so that a vacuum suction force is sufficient to secure the semiconductor package during electrical and optical tests on it. However, reducing the spring forces may lead to less reliability when conducting electrical tests.
It would thus be beneficial to provide an apparatus that is suitable for conducting both optical and electrical tests with higher reliability as compared to the prior art.